Physical and chemical characterization of the 2019 ``black rain{''} event in the Metropolitan Area of Sao Paulo, Brazil

Author(s)

Pereira, Guilherme Martins ^{[1, 2]} ; da Silva Caumo, Sofia Ellen ^[2] ; Grandis, Adriana ^[3] ; Mota do Nascimento, Emerson Queiroz ^[2] ; Correia, Alexandre Lima ^[4] ; Jorge Barbosa, Henrique de Melo ^[4] ; Marcondes, Marta Angela ^[5] ; Buckeridge, Marcos Silveira ^[3] ; Vasconcellos, Perola de Castro ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Dept Atmospher Sci, BR-05508090 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Chem, Dept Chem, BR-05508000 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Inst Biosci, Dept Bot, BR-05508090 Sao Paulo - Brazil

^[4] Univ Sao Paulo, Inst Phys, Dept Appl Phys, BR-05508090 Sao Paulo - Brazil

^[5] Univ Sao Caetano do Sul, Sao Caetano do Sul - Brazil

• Document type: Journal article
• Source: Atmospheric Environment; v. 248, MAR 1 2021.
• Web of Science Citations: 3

Abstract

Aerosols emitted from biomass burning in South American tropical forests have been a concern in the last decades. On August 19th, 2019 darkened precipitation was observed over the metropolitan area of Sao Paulo (MASP), in an unprecedented event termed ``black rain{''}, after intense biomass burning episodes in the South American hinterland. Satellite imagery, back trajectory analyses, and meteorological reports showed air masses transporting thick plumes of biomass burning aerosols originated in part from the Amazon Basin and Bolivia. Rainwater samples were collected in different sites of the metropolitan area, during and after the ``black rain{''} event, and both physically and chemically characterized to assess the possible influence of biomass burning aerosols in the event. The collected samples in the ``black rain{''} event presented high turbidity (above 70 NTU), and biomass burning organic tracers (levoglucosan, mannosan, and galactosan) were observed in higher concentrations in the ``black rain{''} samples than in control ones (e.g. average levoglucosan of 0.33 mu g mL(-1), compared to 0.02 mu g mL(-1) after the event), with deposition fluxes more than three times higher during the event (1.04 mg m(-2) and 0.31 mg m(-2), respectively). The detection of glucose, xylose, and mannose, after hydrolysis of the solid material present in the ``black rain{''} samples, strongly suggested the presence of plant cell wall material derived from the partial combustion of wood and grass matter. Total polycyclic aromatic hydrocarbons (PAHs) concentrations were, in general, higher during the event than in post-event control samples collected in the MASP (on average, almost 15 times higher than after the event), with a higher deposition flux (5.1 and 2.7 mgm(-2) respectively). Overall, there are strong pieces of evidence that the long-range transport of smoke produced in South American forest fires was connected to the precipitation of darkened rainwater over the Metropolitan Area of Sao Paulo. (AU)

• FAPESP's process: 14/50884-5 - INCT 2014: National Institute of Science and Technology of Bioethanol
• Grantee: Marcos Silveira Buckeridge
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 10/15959-3 - SeReNA Project: remote sensing of cloud microphysics and its interaction with atmospheric aerosols
• Grantee: Alexandre Lima Correia
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/01316-8 - URBESP: levels, composition and source APPONTMENT of PM10 and PM2.5 in São Paulo
• Grantee: Guilherme Martins Pereira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/13936-0 - The role of xyloglucan in the cell wall architecture determination in sugarcane
• Grantee: Adriana Grandis
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/23339-1 - Molecular characterization and occurrence of organic compounds in gaseous and particulate phase in atmospheric particulate matter collected in Petrochemical Industry of Capuava (SP)
• Grantee: Sofia Ellen Caumo Miranda
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 16/18866-2 - Detailed observation of the microphysics of aerosols and clouds using the new HARP-CubeSat satellite, the grasp algorithm and in-situ measurements in Amazonia
• Grantee: Henrique de Melo Jorge Barbosa
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 18/16608-1 - São Paulo School of Advanced Science on atmospheric aerosols: properties, measurements, modeling, and effects on climate and health
• Grantee: Henrique de Melo Jorge Barbosa
• Support Opportunities: Research Grants - Scientific Meeting - São Paulo School of Advanced Science
• FAPESP's process: 08/57908-6 - National Institute of Science and Technology of Bioethanol
• Grantee: Marcos Silveira Buckeridge
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants